Investigation of Accelerated Degradation Methods to Cause Blisters for Non-Defective Vinyl Ester Resin Glass Flake Organic Coatings

Organic coatings are applied as a corrosion prevention measure, but their effectiveness may degrade over time. In this study, the acceleration effects of typical degradation methods in non-defective vinyl ester resin organic coatings containing glass flakes such as high-temperature immersion and immersion in chemical accelerators are clarified using physiochemical techniques. Immersion in an acetic acid (AcOH) aqueous solution causes resin swelling, and the behaviors are quantitatively evaluated through gravimetric, thickness, and electrochemical impedance spectroscopy (EIS) measurements. Furthermore, a combined process of immersion in hydrofluoric acid and an AcOH aqueous solution reduces the electrical properties and eventually blisters the thick coating surface. This result suggests that an appropriate combination of the resin swelling and the glass degradation (glass dissolution and/or formation of the gap between glass and resin) decrease mechanical properties of the glass flake coating and causes blisters. In order to help the health diagnosis of the visually non-defective aged glass flake coating, the relationship between the electrical characteristic values and the invisible degradation by accelerated tests is finally indicated.

Evaluation of Fatigue Behavior of Epoxy Coatings used for Potable Water Storage Tanks

In this paper, three types of epoxy-based coatings (Polyamide, pure Polyamine, and Polyamine reinforced by glass-flake) used as a lining for potable water tanks were studied using experimental and finite element methods. Tensile, impact, and fatigue tests were conducted on uncoated and coated AISI 316 stainless steel. The test results show that the applied epoxy based coating improves the mechanical properties, increases of fatigue crack resistance, and enhance the dynamic fracture toughness. The fatigue crack propagation is influenced by the compositions of epoxy coating, and the glass-flake improves the coating resistance to fatigue crack propagation compared to other types.

The Influence of Glass Flake and Micaceous Iron Oxide on Electrochemical Corrosion Performance of Waterborne Silicate Coatings in 3.5% NaCl Solution

Waterborne silicate composite coatings were prepared to replace existing solvent-based coatings for ships. A series of complex coatings were prepared by adding anticorrosive pigments to the silicate resin. Adhesion, pencil hardness, and impact resistance were investigated, and corrosion performance in 3.5% NaCl solution was measured by electrochemical impedance spectroscopy (EIS). The results show that adhesion and impact resistance are high, and that pencil hardness can reach 4H. The curing mechanism for the coatings were investigated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanism of curing reaction in the studied waterborne silicate paint was found to be different from that reported in the literature. When the coatings were immersed in 3.5% NaCl solution for 8 h, there is only one time constant in the Bode plot, and coating capacitance (Qc) gradually increases while coating resistance (Rc) gradually decreases. Glass flake composite coatings have better corrosion resistance by comprehensive comparison of Qc and Rc.

Optical and Mechanical Properties of Highly Transparent Glass-Flake Composites

In this paper, the dynamic mechanic and optical properties of composites made of Polyvinyl Butyral (PVB) and Micro Glass Flakes (MGF) with matching refractive indices (RIs) are investigated. The composite is produced by a slurry-based process using additional blade casting and lamination. It can be shown that a high degree of ordering of the MGF in the polymer matrix can be achieved with this method. This ordering, combined with the platelet-like structure of the MGF, leads to very efficient strengthening of the PVB with increasing content of the MGF. By carefully adjusting the RIs of the polymer, it is shown that haze is reduced to below 2%, which has not been achieved with irregular fillers or glass fibers.

Anti-Corrosion Property of Glass Flake Reinforced Chemically Bonded Phosphate Ceramic Coatings

Glass flake (GF) was used as the reinforcement in chemically bonded phosphate ceramic (CBPC) coatings to promote anti-corrosion property. The crystalline phase, curing behavior, micromorphology and electrochemical performance of the coatings were studied. The results indicate that with the addition of magnesia (MgO), a new bonding phase (Mg3(PO4)2) can be formed, which can help the CBPCs achieve a more compact and denser structure. The effect of the magnesia and the GF additives on curing behavior is obvious: the heat of reaction of the phosphate ceramic materials increases with the addition of the magnesia and the GF, which emphasizes the higher crosslinking density in the phosphate ceramic materials. The phosphate ceramic coatings with the magnesia have a higher impedance value compared with the neat phosphate ceramic coating, while the highest impedance value is obtained with increased content of GF. The corrosion mechanism is mainly contributed by the new bonding phase and GF particles, which can hinder the permeation pathway and make the permeation more circuitous.

The Gas Permeability of Polyolefin Blends Containing a Glass Flake Filler

The results of investigating the influence of the concentration of glass flake filler on oxygen, carbon dioxide, and water vapour permeability in composites based on high-density polyethylene blends are given.